Differentiate between identical volumes

[AlvaroEzq]

Differentiation between identical volumes

Changes to be able to differentiate between identical volumes. In particular there are two cases where the volumes need further filtering:

• The Geant4 sensitive detectors are associated to logical volumes, thus all physical volumes which share the same logical volume will be sensitive volumes even when the user specifies a particular physical volume name in the configuration of the restG4 simulation.
• The daughter physical volumes of a mother volume placed several times in the geometry have the same G4VPhysicalVolume object.

The particular physical volume where the step of the Geant4 simulation is happening, can be obtain using the G4VTouchable. This should be done for every part of the simulation where any kind of physical volume given by the user is used. These are:

• Sensitive volumes
• Active volumes
• Primary generation from volume

Primary generator fixes

I also took the oportunity of this PR to fix a couple of problems with the primary generator from gdml volumes:

• Primary generation from GDML volume is wrong for volumes with rotation #143
• Since nested volumes are accepted in restG4, this has to be accounted in the primary generator from gdml volume if the chosen volume has daughter volumes. With commit 5108a72, the daughter volumes are excluded in the generation of primary particles.

Important

The changes of PR rest-for-physics/geant4lib#146 are needed.

[AlvaroEzq]

The last commit fixes #143